Gasoline composition



United States Patent GASOLINE CGMPOSITION Harry J. Andreas, In, Pitman,N. J., assiguor to Socony Mobil Oil Company, Inc., a corporationof NewYork No Drawing. Application February 19, 1954 Serial No. 411,565

1 Claim. ,(Cl. 44-66) This invention relates to gasoline fuelcompositions for use in internal combustion engines and is particularlyconcerned with new gasoline compositions adapted to provide improvedengine operation under cool and humid weather conditions.

A well known difficulty encountered in the operation of automobileengines in-cool and humid weather is that of frequent engine stallingduring the warm-up period. The trouble is most prevalent in northernclimates during the fall and winter periods. Its cause has been tracedto the formation of ice in the carburetor of the engine. Although thedifiicultyhas existed fora long time, it has become more prevalent thanever in recent years due to the use of more highly-volatile,winter-grade gasolines.

Thus, the evaporation of gasoline in the carburetor produces aconsiderable cooling effect which is more pronounced with the highervolatility gasolines. 'In cool, moist weather, this cooling effect issufiicient to cause condensation and freezing of the moisture present inthe air entering the carburetor. Consequently, in the period before theengine becomes warm, ice is formed which restricts the air-intakeopenings and causes the engine to stall. It has been found thatconditions particularly conducive to stalling difficulties due to iceformation in the carburetor'are ambient temperatures of from about 30 F.to about 65 F., when the relative humidity is above about 65%. Thestalling occurs most readily when the engine is idling and although thefrequency of stalling is greater with gasolines of higher volatility,such as those provided for winter use in northern climates, thedifficulty is experienced with all types of commercial gasolines in alltypes of cars.

It is the object of this invention to provide gasoline compositionshaving anti-icing properties such that substantially stall-freeoperation, under conditions which would normally induce stallingdifficulties, is attained. Other and further objects of the inventionwill appear from the following detailed description thereof.

In accordance with the present invention, it has now been found thatstalling difliculties due to the formation of ice in the carburetor ofan engine can largely be overcome by incorporating in the gasoline asmall amount of glyceryl monooleate.

As is well known to those familiar with the art, a gasoline is a mixtureof hydrocarbons having an initial boiling point varying between about 75F. and about 135 F. and an end-point varying between about 250 F. andabout 450 F. and boiling substantially continuously therebetween.

Glyceryl monooleate provides excellent anti-icing properties in alltypes of gasolines. The gasoline may be comprise of straight-run orcracked petroleum distillates boiling in the gasoline range which havebeen derived from either paraffinic, naphthenic, mixed base or othercrude petroleums. Also, it may comprise products prepared by specialprocesses, such as polymerization, alkylation, hydrogenation, etc. Mixeddistillate and/or processed stocks, including stocks which have beensubjected required for the engine to stall was .noted.

2,857,255 Patented Oct. .21, 1958 12 to -various refining treatments,such as acid extraction, solvent treating, vetc., are all improved withrespect .to their anti-icing character by treatment with glycerylmonooleate.

Carburetor icing tests The ability of glyceryl monooleate to preventengine stalling, under conditions conducive to carburetor icing has beendemonstrated by means of a series of cold-- starting tests. A basegasoline consisting of straight-run component and having the'followingproperties was utilized in the tests.

This gasoline was selected on the basis of its high volatility whichmade it particularly susceptible to stalling under cool, humid operatingconditions.

The test procedure was as follows: A standard Chevrolet engine wasinstalled in a cold room equipped with temperature and'humiditycontrols. With the room temperature maintained at approximately 44 F.and the relative humidity at approximately 97%, the engine was startedand operated for one minute at 2000 'R. P. M., with no load. At the endof the one minute operation, the engine speed was reduced to 500 R. P.M. and the time It had been determined previously that under theseparticular conditions of temperature and humidity, and using .theaforedescribed base gasoline, the engine would stall immediately whenthe speed was cutback after the one minute operation period. A series oftests were conducted employing the base gasoline containing variousconcentrations of the glyceryl monooleate of this invention and otherglyceryl esters of fatty acids in order to determine the amount of theester required to provide a practicable delay in the stalling time andto show the unexpected superiority of the glyceryl monooleate in thisrespect.

It will be observed that the glyceryl monooleate was outstandinglyeffective in terms of the amount required.

It will be appreciated that many commercially available gasolines,including those of the so-called winter grade type, are less volatilethan the gasoline used in the aforesaid tests and are, therefore, lesssusceptible to stalling under stall-inducing weather conditions than thetest gasoline. Nevertheless, such gasolines are prone to producestalling and they are benefited with respect to their stallingtendencies by the use of glyceryl monooleate. As a rule, somewhatsmaller amounts of the additive may be used with gasolines of relativelylow volatility, while somewhat larger amounts may be required for highervolatility gasolines. Broadly, the amount of the additive contemplatedfor use ranges from about 0.003 weight percent up to 0.009 weightpercent, the particular amount depending upon the particular gasoline towhich it is added. The use of from'about 0.006 to 0.009 weight percent,however, is generally preferred.

The glyceryl monooleate can be used in gasolines containing otheradditives designed to improve the gasoline in various other respects.Thus, it will improve the antiicing character of gasolines containingmetallo-organic anti-knock agents, such as tetraethyl lead. Thetetraethyl lead is ordinarily present in amounts of from about 1 toabout 5 cos. per gallon. As is well known, these gasolines ordinarilycontain an organic halide lead-scavenger, such as ethylene dichloride,ethylene dibromide or the like.

The gasolines can also include an anti-oxidant of the polyalkylatedphenol type, such as, for example, 2,6-ditertiary butyl para-cresol;2,4,6-tributyl phenol, 2,4-dimethyl, 6-secondary butyl phenol, or thelike. Suitable amounts of such an anti-oxidant vary from about 0.0004 toabout 0.001 weight percent.

The invention also contemplates the use in leaded gasolines of anadditive capable of inhibiting preignition, particularly in gasolinesdesigned for use in high compression engines. Esters of phosphorusacids, for example triphenyl phosphate, tricresyl phosphate, trimethylphosphate, diphenyl cresyl phosphate and trimethyl phosphite, arecontemplated for this purpose. Phosphorus acid esters containing halogenand sulfur constituents, such as, for example, tri-beta-chloro propylthionophosphate, are also suitable. Such additives are used in amountsof from about 0.01 to about 0.03 weight percent.

The gasolines can further contain additives that deactivate metals, suchas copper, etc., which catalyze oxidation of the gasoline. Metaldeactivators of the Schifi base-type are particularly contemplated.These compounds are produced by the condensation of one mol of apolyamine having two primary amine groups with two mols of an aromaticorthohydroxy-substituted aromatic aldehyde. A particularly efiectivecompound is N,N- disalicylal 1,2-propylene diamine. From about 0.00004to about 0.0004 weight percent of the metal deactivator is ordinarilyused.

Illustrative of specific gasoline compositions contemplated by thepresent invention are the following:

(A) A premium gasoline for use in high-compression engines was preparedas follows: To a gasoline comprised, on a volume basis, of approximately40% thermal, 30% catalytically cracked and 30% straight run components,the following were added:

(a) 0.009 weight percent glyceryl monooleate (b) 0.02 weight percentdiphenyl cresyl phosphate (0) 0.004 weight percent 2,6-ditertiary butylpara cresol (d) 0.0002 weight percent disalicylal, 1,2-propylene diamine(e) 2.5 cc. T. E. L. per gallon References Cited in the file of thispatent UNITED STATES PATENTS 1,692,784 Orelup et al Nov. 20, 19282,599,338 Lifson et al. June 3, 1952 2,600,113 Jones et al June 10, 1952FOREIGN PATENTS 277,326 Great Britain Jan. 7, 1929 486,631 Great BritainJune 8, 1938 683,405 Great Britain Nov. 26, 1952 OTHER REFERENCESChemicals, Glyco Products Co. Inc.; copyright 1944, pages 6, 7 and 14.

Aviation Gasoline Manufacture, by Van Winkle, first edition,McGraw-Hill, 1944, pages 240-241.

